Spray dampening system for lithographic offset printing presses



Aug. 23, 1960 l c. H. BoRcHERs SPRAY DAMPENING sysTEM FoR LITHOGRAPHIC OFFSET PRINTING PRESSES Filed April 3, 1957 6 Sheets-Sheet 1 IIIIIIIIIIIII'I'iillllll Aug. 23, 1960 c. H. BoRcHr-:Rs

SPRAY DAMPENING SYSTEM FOR LITHOGRAPHIC OFFSET PRINTING PRESSES Filed April s. 1957 6 Sheets-Sheet 2 Aug. 23, 1960 c. H. BoRcHERs 2.949.850

SPRAY DAMPENING SYSTEM FOR LITHOGRAPHIC OFFSET PRINTING PRESSES 6 Sheets-Sheet 3 Filed April 3; 1957 Aug. 23, 1960 c. H. BoRcHERs SPRAY DAMPENING SYSTEM FOR LITHOGRAPHIC OFFSET PRINTING PRESSES Filed April 3, 1957 6 Sheets-Sheet 4 NWN.

Aug- 23, 1960 c. H. BoRcHERs SPRAY DMPENING SYSTEM FOR LITHOGRAPHIC OFFSET PRINTING PRESSES Filed April 3, 1957 6 Sheets-Sheet 5 ...771% 2z for* Aug. 23, 1960 c. H. BORGHI-:Rs 2,949,850

SPRAY DAMPENING SYSTEM FOR LITHOGRAPHIC OFFSET PRINTING PRESSES Filed April s, 195'? s sheets-sheet e SPRAY DAMPENING SYSTEM EoR LITHO- GRAPHIC OFFSET PRINTING PRESSES Charles H. Borchers, Warrensville, Ill., assignor to Lithographic Technical Foundation, Chicago, Ill., a corporation of Delaware Filed Apr. 3, 1957, Ser. No. 650,493

13 Claims. (Cl.V 1011-147) My invention relates to spray dampening equipment for lithographie offset presses whereby, as is customary in such printing, the surfaces of the printing plates are dampened before the printing inkV is applied theretoA in order to prevent adhesion of the ink to those parts of such surfaces on which no printing image appears.

One of the objects of my invention is to provide a spray dampening system for lithographie `oifset printing in which the amount of spray reaching lthe plate cylinder may be controlled across the lengthof the cylinder.

Another object of my invention is to provide a spray dampcning system of the aforementioned type in which the spray is automatically cut `off at the cylinder gap;

Yet another object of my invention is to provide such a system in which the size of the dampening particles in the spray may be controlled. y t

It is also an object of my invention to provide apparatus for the purpose stated in which -the'spray maybe controlled around and across the cylinder.

An additional object is to provide a system ofv this sort which causes the spray to cut off at the cylinder gap by less complicated means than those presently used to accomplish this function.

`Other objects and advantages of the invention will be evident from the Ifollowing description, taken together with the accompanying drawings, in which:

Fig. 1 is a partial top plan-view of a' lithographie press equipped with a spray dampener made in accordance with this invention, showing the general position of such spray dampener in relation to a plate cylinder;

Fig. 2 is a rear view in elevation of the'l spray dampener, with the plate which normally coversthe vacuum section removed for better illustration of the vacuum system;

Fig. 3 is a perspective view, partially broken away, of the lithographie press equipped with the spray dainpe'ner;

Fig. 4 is a detailed cross-sectional view of the spray dampener, taken substantially on section line 4-4 of Fig. l and looking in the `direction indicated by the ar'- rows; 4

Fig. 5 is a detailed view of an electrically-controlled solenoid valve and by-pass'used to control air ow in the dampener system;

Fig. 6 is a longitudinal view of, a sprayehamber formf ing a part of the dampener, taken substantially on seetion line 6-6 of Fig. 4 and looking in the directionlindicated by the arrows;

`ited States y Fig. 7 is a detailed top plan View' of a spray'noz'zle which introduces a liquid spray into the spray dampener;

Fig. 8 is a detailed frontal elevation,'partially in cross'- section, of the spraynozzle;

Fig. 9 is a sectional viewfof the spray dampener taken substantially `on section line 9-9 of Fig. 4 and looking 2,949,850 Patented Aug. 23, 1960,

icc

illustrated, some ofthe diiculties encountered with exist? ing dampening systems, and prior attempts to overcome' them, will be referred to, since it is believed that this willI be helpful in understanding the problems involved andl the ways in which they are solved by the present inVen-" tion. Dampening rollers are most commonly used to dampen lithographie offset plates. These dampening rollers' re' ceive moisture from a fountain by means of distributing rollers, and transfer such moisture to the rotating lithographicfplate by rolling contact.

Several difficulties' have been encountered in the use of the dampening rollers, some of which are: soiling of the roller with ink, causing `decreased dampening efficiency of the roller, and necessitating changing the roller; due to the nature of the moisture transferal, an adjustment of the amount of moisture reaching the plate is prolonged, and sinceV the rollers are constantly being soiled, an adljustrnent is, at best, quite temporary; and by virtue of the rolling' contact of the dampening roller with the plate, a certain amount of damaging abrasion occurs on the lithographie plate.

In attempting to overcome the difficulties encountered withydampening rollers, various spray dampeners have beenproposed. These proposed spray dampenersy general-` ly are of two types, namely, l) those in which the plates are sprayed by a series of nozzles, and (2) those in whic 't the spray medium is introduced into a chamber running parallel to the plate cylinder and having a slot through whichy the spray is directed to the cylinder. Both of these schemes are subject to the objection that either they do not. provide a method of controlling spray around and across the cylinder, or, if they do, they involve rather complex, mechanisms for doing so. i j

Referring rst to Fig. 3 of said drawings, the'reference numeral 10 indicates a lithographie press including a plate cylinder 11 affixed to a plate cylinder shaft 12. A` litho-y graphie plate 13, shown in Fig. l, is affixed to the cylin-v der 11, and has ink conducted thereto by an inking roller 14 which` is affixed to a mandrel 15. ,j y v The press 10 also includes two inclined tracksy 1,6, provided with teeth 17 at the outer edge thereof, positioned respectively at either side thereof. A base portion 18, upon'which the machine of this invention is assembled, is slidably mounted upon each of said tracks 16. At the lower vendV of each of said tracks 16 is a vertical stop 19.

AE threaded post 20, through which passes a set screw 21 which is aligned with the stop 19, is -aflixed to theouter side of each of said bases. A crank 22 is attached to an axle 23 extending between the bases 18 and accommodating gears 24, aliixed thereto at either end. The gears 244 are in mesh with the teeth l1'7 of the tracks 16, so that by turning the crank 22, the bases 18 and the machine assembled thereupon can be caused to move along the traeki16. The set screws 21 and the stops 19 allow*k the bases 18 and the mechanism assembled thereupon to be critically positioned upon the tracks 16.

Anarm 25, extending vertically from each base 18 `is attached thereto by bolts 26. A slot 27, provided in the center of the arm 25 allows a threaded rod 28, extending from either end of an elongated chamber 29, tol pass` therethrough. A =knurled nut 30, screwed onto the rod 28 allows the chamber 2,9 to bel secured tothe arm 25.

t, vrBetween each end of ythe chamber 29 and the arm 3 is another arm 31 also secured to the rod 28. The arm 31 provides support for spraying means, described more fully hereinafter.

f The chamber 29, best shown in Fig. 4, is an elongated container or chamber, preferably cylindrical inshape,A having a longitudinal opening 32 in Vone side thereof and having metal plates 33 and 34 extending on either side thereof and closed at their ends by closures 35. -The lower plate 34 is inclined toward the upper plate 33, so that liquid which might collect on the lower plate 34 will not drip outwardly therefrom. A metal rod 36, located beneath said opening 32 and extending the length of the chamber 29, has'a plate 37 connected thereto which extends through the opening 32 and between the plates 33 and 34.

The upper plate 33 is provided with thumbscrews 38. 'The screws 3S are aligned in two rows, one row being aligned on .a vertical plane, and the other row being aligned at an angle from the vertical plane (see Fig. 9). Those screws aligned on a vertical plane, are threaded through collars 39 attached to the plate 33 and said screws are attached to the plate 37. The other screws 38 simply pass through the plate 33 and screw through collars 39 -attached to the plate 37. By properly manipulating the screws 38 it is possible to Warp the plate 37 and, in this manner, restrict a portion `or all of the opening 32 (see Fig. 10). It will be understood that by restricting lthe opening 32, the outward flow of any spray produced within the chamber 29 will be impeded. It should be further understood that irregularities in moisture application usually occur as gradual gradients across the width of the printing plate and that by use of the above-described warpable plate correction can be made in similar gradients.

The chamber 29 is provided with openings 41 located to the `rear and slightly above the opening 32 to accommodate spray nozzles 42 (see Figs. 4 and 6). Each spray nozzle -42 is secured in a block 43, which has -a hole 431 therein to accommodate it, by means of a set screw 44 (see Figs. 7 and 8). The blocks 43 are spaced along a segmented rod 45, each end of which extends through an #arm 31 and has a knurled knob 46 axed thereto (see Figs. l and 2). Two tension screws 47, screwed into each of the arms 31 and located on either side of the aperture (not shown) through which rod 45 passes, keep the rod from rotating, except when desired, and maintain the nozzles 42 in position.

'The spray nozzle 42 includes -a body 48 which eneloses a hollow lter section 49 having slots 50 circumferentially arranged thereabout. A screen 51 surrounds the iiltcr section 49 and is secured therearound by crimping under a screw 52 which screws into one end of the filter section. A spray head 53, having an aperture 531 therein, is secured -to the body 4S 'by means of a collar 54. To assure a liquid-tight joint between the body 48 and spray head 53, a washer 55 is positioned therebetween. The entire nozzle is `force-itred into a sleeve 56 which tits into the block 43.

Each nozzle 42 emits a spray in a ltan-shaped pattern. It is essential that the edges of such spray pattern do not overlap the spray pattern from another nozzle. As shown in Figs. 7 and 8, each segment of the rod 45 extends only part way into holes 57 which are tapped in either side 4of the block 43 in which the nozzle 42 is secured. A set screw 58 extends into the hole 57, se-V curing the rod 45 into said hole. By releasing the tension on each of the set screws 58 of ablock 43, the block and nozzle may be moved slightly along the length of the rod 45, so that spray patterns from dilerent nozzles will not overlap.

The spray pattern of `a nozzle 42 can be rotated from the plane which it normally has by lowering the set screw 44 which holds the nozzle in the block 43 'and revolving the nozzle about its axis of symmetry. By manipulating the screw 44, it is also possible tov adjust the distance the nozzle 42 will extend from the block 43.

A pipe 59, best shown in Figs. 1 and 2, conducts a Idampening agent, such as water, to the nozzles 42. The nozzles are connected ,thereto by means of T-joints 60 and an elbow 61. The pipe S9 is fabricated from copper or other yieldable material, and slack -is provided between each of the nozzles 42 so that nozzle adjustments, heretofore described, may be made.

The dampening agent conducted to the nozzles 42 is emitted therefrom in a tine spray. The nozzles generally introduced the spray into the chamber at a downward angle. A primary classication of the particles of the dampening agent occurs -upon the spray leaving the nozzles whereby larger particles, due to momentum and gravitational force, are unable to navigate the curved path required in order to allow them to leave the opening 32. Particles not Ileaving the chamber 29 collect on the bottom thereof, and are removed by drains 62 (see Fig. 6) which connect with .the pipes 63. Upon leaving the chamber l29 by the drains 62, the dampening agent is re-cycled by pipes 63 back into the system.

To c-ause the spray produced in the chamber 29 to leave the opening 32 and dampen a lithographie plate 13 attached to the plate cylinder 11, air is introduced into the chamber to bring about a general increase in pressure therein. Pipes 64, provided with holes 65 lalong their length, are affixed to the rear wall of the chamber 29 (sce Figs. 6 and 9) beneath the nozzles 42 to emit air into the chamber.

Air (from a source not shown) is yconducted by a pipe 66 to a T-joint 67. Extending from either side of said T-joint'67 are pipes 68 which connect, by means of elbows 69, to the pipes 64. By varying the pressure of the air supplied to the pipes 64, it is possible to regulate the amount of spray leaving the cylinder 29. Arrows drawn near the :aforementioned pipes indicate the direction of air flow therethrough.

, Another means of controlling the amount of spray leaving -the chamber 29 is by creating a partial vacuum therein. Two holes 70 are drilled in Ithe rear wall of the chamber 29 (see Fig. 6). An air-activated air pump 71 is aixed to the Arear Wall of the chamber behind each of the holes 70 (See Fig. 9). A pipe 72 extends from each of said pumps 71 to a T-joint 73 (see Fig. 2). The T-joint 73pis connected, by a length of pipe 74, to an Aelbow `75,.which in turn, is connected to a pipe 76 leading to an air source (not shown).

When air is supplied 'to the air pumps 71, which operate on the venturi principle, it causes a partial vacuum to be created Within the chamber 29, impeding in part, or stopping completely, the dow of spray therefrom. The strength of the vacuum created -is dependent upon the amount of air supplied to the pumps. It is not deemed necessary to explain in detail the operation of the air pumps, since any manner of creating a vacuum within the chamber would work equally las well. Arrows inscribed near the aforementioned elements indicate the direction of air flow therethrough.

The air pumps 71 and their necessary connections are enclosed a vertical wall 77, a horizontal wall 78, and end closures 79. The vertical wall is provided with a cutfout (see Fig 2) .to lallow -access to the air pumps 71 and their connections. Threaded studs S0 stick out from the edge of the cut-out and a plate 81, perforated tol allow it .to iit over said studs, is normally placed over the cut-out. Nuts 82 are threaded onto the studs 80 to secure the plate 81 (see Fligj4). The enclosure formed bythe elements is referred to as a vacuum section.

'.f A hole 83 is provided in each of the enclosures 79 and an elbow-shaped exhaust pipe 84 cooperates therewith. YEach of the exhaust pipes 84, as shown in Fig. 3, is connected by a sleeve 85 to an exhaust extension 86. The holes 83 are necessary to prevent the build-up of air pressur@ Within the vacuum section, since any build-11p 0f air pressure therein would decrease the eiiiciency of theair: pumps`71. L

Anvadjustable-cam87, best shown in Figs. 1l, l2 and 13 isattached to the plate'cylinder shaft 12 insuchlmanner that the raised portion thereof is aligned with the plate cylinder gap in which plate'clamps (not shown),` which secure the plate 1-3 to the plate cylinder 11, arel located. The cam consists basically of two semi-circular sections 88 and- 8 9.Y Section 488 hasa raised portion 90, andsection-89 a raised portion 91. The portion 90 has a tongue 92-extending therefrom which tits into a slot 93 provided in the center of the raised portion 91. The tongue 92 is providedwith holes 94 along its length. Theraised por-v tion 91y is likewise provided with a hole (not shown). It ispossible to adjust the height ofthe cam surface by inserting the tongue 92 the desired distance into the slot 93 and securing it` therein by inserting. apin 96 through the hole 94 and the holein portion `91. The sections 88 and 89 are joinedby bolts 97 which secure the cam 87 to the plate cylinder shaft'12'.

A follower arm 98 of a feather switch 99 is caused to ridevupon the'cam surface. Two wires 101 and -102 are connected to the feather switch (see Fig. 5). The wire 101 connects with one pole of a galvanic circuit, and wire 102 connects to a solenoid valve 103 junctured into the pipe 76 between the air supply and the T-joint 73 (see Figs. 5 and 9). The solenoid valve 103 has a wire 104 connected thereto, in additionfto the wire 102. The wire 104 is connected to that polelof'- a galvanic circuit opposite the poleto which the wire 101-is connected.

As the cam87 causes the follower arm 98 of the feather switch 99 to rise, the-follower arm closes the switch, activating the'valve 103 to open, allowing air to rush through the pipe 76. The air so released activates the airpumps 71, which create a partial vacuum of such amount inthe chamber 29 that no spray may pass therefrom.- In this manner spray is kept from reaching. the cylinder gap.

A by-pass 105 is provided around the valve103- (see Fig. 5). A needle valve 106 is provided in said by-pass 105 so that a small amount of air maybe allowed to pass the valve 103 when the latter is closed, thus permitting the pumps 71 to operate at a limited rate to create a-slight vacuum in the chamber 29 so the amount of moisture reaching the printing plate during the time that the spray is beingemitted from the cylinder may be reduced.

Since certain changes can be made in the foregoing construction and different embodiments' of the invention canbe made without departing from the spirit and scope thereof, it is intendedvthat all matter shown in the accompanying drawings and described hereinbeforeA shallbe interpreted as illustrative anclV not in a limiting sense.-

l". A spray dampening system vfor lithographie offset presses which include a rotating printing plate cylinder, such system comprising: a chamber arrangeable in close proximity to said cylinder and having a slot therein opening toward said cylinder; means for introducing into said chamber an atomized spray of a dampening agent; means for increasing the air pressure Within said chamber to cause the atomized spray introduced therein to iilow through said slot; and means for at time creating a partial vacuum within said chamber to impede the ow of said atomized spray from the slot.

2. A spray dampening system for lithographie olset presses which include a rotating printing plate cylinder, such system comprising: a chamber arrangeable in close proximity to said cylinder and having a slot therein opening toward said cylinder; means for introducing into said chamber an atomized spray of a dampening agent, means for increasing the air pressure within said chamber to cause the atomized spray introduced therein to now through said slot; means for at times creating a partial vacuum within said chamber to impede the flow of said atomized spray from the slot; a warpable plate positioned in said slot; and means for warping said plate in such v6 manner as to restrict saidslot, to a' greater or less extent, in any desired area thereof. ,v l

3. A spray dampening system for lithographie oiset presses which include a rotating printing plate cylinder, such system comprising: achamber arrangeable in close proximity to said cylinder and having a slot therein opening toward said cylinder; means, adapted for rotatable adjustment about its axis of symmetry, for rotatable adjustment about a horizontal axis perpendicular to its axis of symmetry, for linear adjustment-along its axis of symmetry, or for adjustment laterally in relation to said chamber, for introducing into said chamber an atomized spray of a dampening agent; means for increasing the air pressure within said chamber to cause the atomized spray introduced therein to ow throughsaid slot; and means for at times creating a partial vacuum within said chamber to impede the flow of said atomized spray from the slot.

4. A spray dampening system for lithographie olset presses which include a rotating printing plate cylinder, such system comprising: a chamber arrangeable in close proximity to said cylinder and having a slot therein opening toward said cylinder; means for introducing into said chamber anv atomized spray of a dampening agent; means for incr/easing the air pressure within' said chamber to: cause the atomized spray introduced therein to ow through said slot; means for creating cyclieally and for a portion only of the cycle of spray application to the cylinder a partial vacuuml Within :said chamber to impede the flow of saidV atomized spray from said slot; and means for correlating said last-mentioned means with the rotation of said printing cylinder whereby the spray may be cut-off at a predetermined point on the latter.

5. A spray dampening system for lithographie offset presses which include a rotating printing plate cylinder, such system comprising: a chamber arrangeable in close proximity to said cylinder and having a slot therein openf ing toward said cylinder; a warpable plate positioned laterally in said slot; meansforwarping said platein such manner as to restrict the opening of said slot; means for introducing into said chamber anatomized spray of a dampening agent; means for increasing the air pressurey within said chamber to cause the-spray introduced therein to flow through said-slot; means forcreating cyclieally and for a portion only of the'cycle` of spray application to the `cylinder a partial vacuum Within saidchamber to impede the W of spray from said slot; and means-for correlating said last-mentioned meansY with the rotation of said print'n ing cylinder whereby the spray may be cut off'at a predeterminedpoint onthe latter.

6. In a spray dampener for lithographie olset presses having a spray-control chamber withan outlet opening therein and means for producing an atomized sprayy of a dampening agent in said chamber, a mouth structure comprising: two plates positioned along the edges of said opening, one thereof being inclined toward the other; a warpable plate positioned between said plates; a rod secured to the dampener to which one edge of the warpable plate is attached; and means for warping said plate to vary the amount of the spray at different points along said opening.

7. In a spray dampener for lithographie offset presses having a spray-control chamber with an outlet opening therein and means for producing an atomized spray of a dampening agent in said chamber, a mouth structure comprising: two plates positioned along the edges of said opening, one thereof being inclined toward the other; walls for closing the space between said plates at their ends; a warpable plate positioned between said plates; a rod secured to the dampener to which one edge of the warpable plate is attached; and means for warping said plate to vary the amount of the spray at different points along said opening.

8. In a spray dampener for lithographie oifset presses having a spray-control chamber with an outlet opening therein and means for producing an atomized spray of a dampening agent in said chamber, a mouth structure comprising: two plates positioned along the edges of said opening, one thereof being inclined toward the other; a Warpable plate positioned between said plates; a rod secured to the dampener to which one end of the warpable plate is attached; and adjusting elements located at intervals along said warpable plate for warping same.

9. A spray dampening system for lithographie offset presses which include a rotating printing plate cylinder and means, comprising a cam rotatable with thecylinder, a cam follower coacting therewith and a switch actuated by said follower, for stopping the spray at a gap area in the cylinder, such system comprising: a chamber arrangeable in close proximity to said cylinder and having a slot therein opening toward the cylinder; means for producing an atomized spray of a dampening agent in said chamber; and pneumatic means for cyclically, and for a portion only of the cycle of spray application to the cylinder, impeding the ilow of spray from said chamber, said means including a device for creating a partial Avacuum within the chamber and means activated by the closing of said switch for causing operation of said vacuum-creating device, whereby the spray is periodically cut oi at said gap area on the cylinder upon successive appearances thereof opposite said slot.

10. In a spray dampener for lithographic offset presses which includes a chamber adapted to have spray introduced therein, a spray assembly comprising: a nozzle supporting shaft rotatably mounted adjacent to said chamber and extending approximately the full length thereof; a plurality of nozzle housings mounted on said shaft for linear and rotatable movement thereon; and a plurality of spray nozzles mounted within said housings, each nozzle being rotatably mounted in its respective housing for rotation about the axis of symmetry of said nozzle and for linear movement along said axis.

11. In a spray dampener for lithographie offset presses which includes a chamber adapted to have spray introduced therein, a spray assembly comprising: a nozzle supporting shaft rotatably mounted adjacent to said chamber and extending approximately the full length thereof; a plurality of nozzle housings mounted on said shaft for linear and rotatable movement thereon; a plurality of spray nozzles mounted within said housings, each nozzle being rotatably mounted in its respective housing for rotation about the axis of symmetry of said nozzle and for linear movement along said axis; and means for conducting a liquid to said spray nozzle provided with slack therein to permit the aforementioned movements of said housings.

12. A spray dampening system for lithographie offset presses which include a rotating printing plate cylinder,

suchsystem comprising: a chamberarrangeable in close proximity to said cylinder and having a slot therein openf` ing toward the cylinder; means for producing an atomized spray of dampening agent in said chamber, lsaid-means including a plurality of nozzles whichare aimed substantiallytowards said slot but slightly downwardly thereof in such a manner that the particles o f spray-must navigate an upwardly curved path withoutimpinging any portion of said chamber in order to beemitted therefrom; means for introducing air under pressure into the chamberin an area out of the direct path of the spray 'through -the chamber whereby, by-'thev general increase of the air pressure throughout the chamber, rather than by direct-impingement of the air onto said dampening agent and propulsion of the same thereby, the smaller and more volatile particles only of the-spray 'are caused to pass along said curved path and onto the printing plate on the cylinder; and spray deecting means arranged to be impinged by the larger particles of said spray which are unable to navigate said curved path whereby said larger particles are caused to be precipitated to -the bottom of the chamber.

13. A spray dampeningsystcm for lithographie offset presses which include a rotating printing plate cylinder, such system comprising: a chamber arrangeablc in close proximity to said cylinder and having a slot therein opening toward the cylinder; means for producing an atomized spray of dampening agent in said chamber, said means including a plurality of nozzles vwhich are aimed substantially towards said slot but slightly downwardly thereof in such a manner that the particles of spray must navigate an upwardly curved path Without impinging any portion of said chamber in order to be emitted therefrom; and means positioned in au area of the chamber out'of the direct path of the spray for increasing fthe pressure within said chamber to an amount which exceeds atmospheric pressure whereby the smaller particles of the spray will be carried along said curved path by the general increase of pressure within'the chamber and be emitted through said slot and Ithe larger particles thereof will,due to their greater weight and momentum, be unable to navigate said curved path and be precipitated to the bottom of the chamber.

References Cited in the file of this patent UNITED STATES PATENTS 1,083,528 Fellerer Jan. 6, 1914 2,108,984 Grembecki Q Peb. 22, 1938 2,300,455 Lukats Nov. 3, 1942 2,389,730 Iler Nov. 27, 1945 2,586,480 Ras Feb. 19, 1952 

